This app draws a translucent mask over screen, it can : * Block blue light, for your health. * Dim screen at night, feel comfortable. Similar to iOS Night Shift. Blue light is bad for health, learn more: www.bluelightexposed.com https://en.wikipedia.org/wiki/High-energy_visible_light www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side Terms of Use: http://diaohs.com/legal/terms